Well here is my negative experience with sleeping with freshlook color contacts, just over the last night i happen to fall asleep with my color contacts while traveling, i totally pasted out in my seat, 5 hours, and when i woke up my left eye was almost stuck,

I concluded that the left color contact was going on me, its been a few weeks i had them on and one day i remember finding that left contact in the contact case stuck to the cap, you know they dry up so been that it was like this for about a few hours i figured its fine, but i did notice it was a tid blury, so if i can speak from my experience alone on this one i do think its dangerous now, i put drops in my left eye but had to sleep a few hours until i had no more pain, it hurt like as if their was a over sized contact when i blinked, so as far as i am concerned i would avoid sleeping with contacts more then a week old, when the contacts are wearing out, i doubt you want this problem i had, i was scared cause it took hours to stop hurting, plus it was blury from my left eye for a hour.